Children with chronic cholestasis have significant osteopenia. The present proposal is evaluating the role of magnesium deficiency and the effect of repletion on bone accretion in children with chronic cholestasis. Results from 7 subjects have been published. Additional subjects are being recruited to verify that the preliminary results are confirmed. During the last study period, 3 additional subjects were studied with one completing the study and one continuing repletion. Additional subjects are being recruited.